Enzymes in the in-situ pellicle of children with different caries activity

The present study investigated, for the first time, enzymes in the in‐situ pellicle of children. Furthermore, it was purposed to detect glucosyltransferase (GTF) isoforms in each child's pellicle. Twenty‐four children (5–9 yr of age) participated in the study. Twelve were caries free with no decayed, missing, and filled teeth (dmft), whereas 12 had active caries (dmft ≥ 2, indicating at least two untreated carious lesions). Bovine enamel slabs, fixed on individual upper jaw splints, were utilized for pellicle formation in situ. After 3 and 30 min, samples were tested for amylase, lysozyme, and peroxidase activities; total GTF activity was examined only in the 30‐min pellicle. Gold‐immunolabelling was used to quantify the GTF B, C, and D isoforms in the pellicle by transmission electron microscopy (TEM). All enzymes tested were detected in the children's in‐situ pellicle in an active conformation, and there were no significant differences in their levels of activity between caries‐free and caries‐active children. All GTF isoforms were found to be randomly distributed within all pellicle layers, althoug GTF B was only detected very sporadically. A significantly higher amount of GTF D was detected in the pellicle of caries‐active children. Pellicle formation in children is characterized by uniformity and selectivity. Glucosyltransferase D might represent a possible biomarker for high caries risk in children.